Synergistic Manipulation of Zn2+ Ion Flux and Desolvation Effect Enabled by Anodic Growth of a 3D ZnF2 Matrix for Long-Lifespan and Dendrite-Free Zn Metal Anodes.

Aqueous rechargeable Zn metal batteries have attracted widespread attention due to the intrinsic high volumetric capacity, low cost, and high safety. However, the low Coulombic efficiency and limited lifespan of Zn metal anodes resulting from uncontrollable growth of Zn dendrites impede their practical application. In this work, a 3D interconnected ZnF2 matrix is designed on the surface of Zn foil (Zn@ZnF2 ) through a simple and fast anodic growth method, serving as a multifunctional protective layer. The as-fabricated Zn@ZnF2 electrode can not only redistribute the Zn2+ ion flux, but also reduce the desolvation active energy significantly, leading to stable and facile Zn deposition kinetics. The results reveal that the Zn@ZnF2 electrode can effectively inhibit dendrites growth, restrain the hydrogen evolution reactions, and endow excellent plating/stripping reversibility. Accordingly, the Zn@ZnF2 electrode exhibits a long cycle life of over 800 h at 1 mA cm-2 with a capacity of 1.0 mAh cm-2 in a symmetrical cell test, the feasibility of which is also convincing in Zn@ZnF2 //MnO2 and Zn@ZnF2 //V2 O5 full batteries. Importantly, a hybrid zinc-ion capacitor of the Zn@ZnF2 //AC can work at an ultrahigh current density of ≈60 mA cm-2 for up to 5000 cycles with a high capacity retention of 92.8%.